Police spray Ugandan opposition party leaders with colored water during demonstrations in the capital Kampala, May 10, 2011. President Yoweri Museveni has vowed to crush the protests and blamed rising food and fuel costs on drought and global increases in oil prices.

Police spray Ugandan opposition party leaders with colored water during demonstrations in Kampala.

Ugandan opposition politician Olara Otunnu, center, stands with his supporters following an attack with water cannons by Ugandan police after he refused to stop his protest march through central Kampala on May 10, 2011 . Ugandan police on Tuesday arrested opposition leader Nobert Mao who attempted to hold a meeting at a public square in the capital Kampala. Mao, who had been briefly detained last week, was dragged into a van by a handful of plain clothed police officers after a standoff with security forces at Kampala's Constitutional Square as opposition leader, Olara Otunnu, retreated after water cannon and tear gas were fired at them to disperse around 20 opposition members.

An Ugandan opposition supporter reacts after police officers fired with water cannons during a protest march through central Kampala.

A military police officer walks past a barricaded road in Kampala, Uganda on April 29. At least one person was killed when Ugandan police fired live bullets and tear gas on Friday to disperse crowds protesting the arrest a day earlier of opposition leader Kizza Besigye, a Reuters witness said.

Ugandan soldiers shoot at demonstrators, who pelt them with rocks from apartment buildings, during riots in Kampala on April 29.

People carry away a woman who fainted after being overcome by teargas during riots in downtown Kampala on April 29.

A plainclothes policeman smashes the car window of opposition leader Kizza Besigye in Kampala, Uganda on April 28.

Another police officer tear gases Besigye in his car.

A policeman goes after a sympathizer of opposition leader Besigye.

Besigye, center, wipes his face while he is dragged away by two plainclothes policemen.

Besigye sits in the Kasangati police station on April 29 after he was detained and attacked with teargas by the police earlier at Mulago roundabout in Kampala.